Color stable viscous hydrocarbon oil



Patented Aug. 9, 1938 PATENT OFFICE COLOR STABLE VIECIZSUS HYDROCARBON Bernard H. Shoemaker and Clarence M. Loane,

Hammond, Ind.,

assignors to Standard Oil Company, Chicago,.Ill., a corporation of Indiana No Drawing. Application August 16, 1937-,

. Serial No.159,370

10 Claims.

This invention relates to a method of protecting viscous hydrocarbon oils against discoloration and. in particular, to the color stabilization of hydrocarbon oils, such as lubricating oils, turbine oils, electrical insulating oils and the like.

Hydrocarbon oils of the type defined deteriorate in colorand appearance during use and when kept in storage over long periods. Since the deterioration in color and appearance is accompanied by more or less impairment of the oils in other respects, it is desirable that such oils be inhibited against discoloration.

We have found that by adding to such oils from about 0.001% to about 5%, and'preferably from about 0.01% to about 0.5% of certain metallic alcoholates and thio alcoholates, the deterioration of color is reduced to a large extent. These metallic alcoholates or thio alcoholates have the general formula M(XR) 3 0r M(XR) z in which M is a metal selected from the group consisting of aluminum and zinc, X is an element selected from the group consisting of oxygen and sulfur, and R is a radical selected from the group consisting of an alkyl radical, an aryl radical, an aralkyl radical and a hydro aryl radical. The alkyl radical is preferably one containing at least three carbon atoms in the radical.

As specific examples of the alcoholates or thio alcoholates which may be effectively used are:

Aluminum propylate, Al(OCaH1) 3 Aluminum butylate, AI(OC4H9) 3 Aluminum amylate, Al (0052111) 3 Aluminum laurylate, Al(OC12I-l2t) 3 Aluminum phenylate, Al(OCtH5)a Aluminum cyclo hexylate, Al(O(cyclo)CtH1i)a Aluminum thio butylate, Al(SC4H9) a Zinc propylate, Zn (OCaH'D 21 Zinc butylate, Zn(OC4I-I9) 2 Zinc amylate, Zn(OC.-.H11)z Zinc laurylate, Zn(OC12I-Iza) a Zinc phenylate, Zn(OCaH5) a Zinc cyclo hexylate, Zn(0(cyclo) Cal-I11) 2 Zinc thio butylate, Zn(SC4H9) 2 Our invention contemplates the use of the cor responding isomers of any of the above compounds and mixtures of the alcoholates and/or thio alcoholates, such as ates which are a mixture of alkyl alcoholates having 12 to 18 carbon atoms in the alkyl chain but predominately dodecyl and tetra decyl derivatives.

The alcoholates or thio alcoholates may be prepared by treating themetal with an alcohol or the following specific example. An S.

for example the laurylmercaptan using iodine or tin tetra chloride as a carrier. For example, aluminum butylate may be prepared by treating aluminum with butyl alcohol in the presence of iodine. The reaction which takes place may be illustrated by the following equation:

The corresponding thio alcoholates may be prepared by substituting the corresponding mercaptan for the alcohol in the above equation.

The efficacy of our invention is illustrated by A. E. 20 motor oil prepared from Mid-Continent crude oil, and the same oil containing (1) 0.25% of aluminum butylate and (2) 0.25% of zinc butylate were heated at 220 F. for a period of several days and the color periodically determined with the following results:

, 220 F. color stability,

N. P. A. color Oil initial 2 days 4 days Control l 3.0 4.8 3+ Control-+0.25% zinc butylate 3.0 3. 7 Control+0.25% aluminum butylate 3. 0 3. 4 3. 7

The effectiveness of aluminum and zinc alcoholates in inhibiting color formation is well demonstrated by the above results, in which the color of the control after {1 days was too dark to transmit light, while the sample with 0.25% aluminum butylate had substantially the same color after 4 days that it had at the start of the test.

While we have described our invention by reference to a preferred embodiment thereof we do not wish to be limited to the specific examples which are merely set forth to illustrate our invention and not intended to be a limitation thereof, except insofar as defined in the appended claims, which should be given the broadest interpretation permitted by the prior art.

We claim:

1. A color stable viscous hydrocarbon oil containing from about 0.01% to about 5% of a metal alcoholate selected from the group consisting of compounds having the general formulas M(XR) a and M(XR.) 2 in which M is a metal selected from the group consisting of aluminum and zinc, X is an element selected from the group consisting of oxygen and sulfur, and R is a radical selected from the group consisting of an alkyl radical, an

aryl radical. an aralkyl radical and a hydro aryl radical.

2. A color stable viscous hydrocarbon oil containing a small proportion of a metal alcoholate selected from the group consisting of compounds having the general formulas M(OR) a and M(OR) a in which M is a metal selected from the group consisting of aluminum and zinc and R is a radical selected from the group consisting of an alkyl radical, an aryl radical, an aralkyl radical, and a hydro aryl radical. g

3. A color stable viscous hydrocarbon oil containing a small proportion of a.meta1 alcoholate selected from the group consisting of compounds having the general formulas M(OR): and M(ORM in which M is a metal selected from the group consisting of aluminum and zinc, and R is an alkyl radical containing at least three carbon atoms.

viscous hydrocarbon oil con- 0.01% to about 0.5% of aluviscous hydrocarbon oil con- 0.01% to about 0.5% of zinc portion of a metallic alcoholate selected from the group consisting of compounds having the general formulas"M(XR)a and M(XR): in which M is a metal selected from the group consisting of aluformulas M OR) 3 minum and zinc, X is an element selected from the group consisting of oxygen and sulfur, and R e is a radical selected from the group consisting of an alkyl radical. an aryl radical, an aralkyl radical and a hydro airy] radical.

7. The method of color stabilizing viscous hydrocarbon oils of the class consisting of lubricating oils, turbine oils and electrical insulating oils which comprises adding thereto a small proportion of a metal alcoholateselected from the group consisting of compounds having the general and M(OR): in which M is a metal selected from the group consisting of aluminum and zinc, and R is an alkyl radical containing at least three carbon atoms.

8. A color stable viscous hydrocarbon oil which comprises addingthereto from about 0.01% to about 0.5% of a metal alcoholate selected from the group consisting of aluminum butylate and zinc butylate.

9. The method of stabilizing viscous hydrocarbon oils which comprises adding thereto a small proportion of a metal alc'oholate selected from the group consisting of compounds having the general formulas M(OR): and M is a metal selected from the group consisting of aluminum and zinc, and R is an alkyl radical having at least 3 carbon atoms.

10. A color stable viscous hydrocarbon oil containing about from 0.001% to about 0.5% aluminum laurylate.

BERNARD H. SHOEMAKER. CLARENCE M. LOANE. 

